Megan Fox Appears in Machine Gun Kelly's Steamy New Music Video

Just a few days after Megan Fox's estranged hubby addressed marriage trouble rumors -- she's the star of Machine Gun Kelly's steamy new music video.

Yep, it's true ... Megan's in MGK's new vid for his song, ''Bloody Valentine,'' where he and she play some sort of a couple who seem to be cooped up in his crib -- and there's a whole lot of sexy outfits and partial nudity in bed to go around.

The video's very intimate, and MF sure seems comfy in Kelly's company here -- which makes sense, we suppose, since they've been hanging out a lot lately. Photos of them riding in Machine Gun Kelly's car surfaced this weekend, which raised a lot of eyebrows.

This is also tough to watch -- especially if you're Brian Austin Green -- considering Megan's gung-ho about this collab herself. She plugged it on her own IG as well.

Of course, Brian -- who Megan is still technically married to, with no current divorce filing -- dished on how they recently grew apart, and how Megan ended up meeting MGK in the first place. It was a sad tale ... he says he had a dream she became distant after returning home from a movie shoot with the guy, and it became reality.